The correct option(s) regarding the complex C o e n N H 3 3 H 2 O 3 + :- (en =   H 2 N C H 2 C H 2 N H…

1. It has two geometrical isomers
2. It will have three geometrical isomers if bidentate 'en' is replaced by two cyanide ligands
3. It is paramagnetic
4. It absorbs light at longer wavelength as compared to ${\left[Co\left(en\right){\left(N{H}_3\right)}_4\right]}^{3+}$

Solution

$\left(i\right)$ ${\left[Co\left(en\right){\left(N{H}_3\right)}_3\left(H_{2}O\right)\right]}^{+3}$ complex is type of $\left[M\left(AA\right)b_{3}c\right]$ have two G.I.

$\left(B\right)$ If (en) is replaced by two cyanide ligand, complex will be type of $\left[M{a}_3{b}_{2}c\right]$ and have 3 G.I.

$\left(iii\right)$ ${\left[Co\left(en\right){\left(N{H}_3\right)}_3\left(H_{2}O\right)\right]}^{3+} have d^6 configuration \left(t_{62g}^6\right)$ on central metal with SFL therefore it is dimagnetic in nature.
$\left(iv\right)$ Complex ${\left[Co\left(en\right){\left(N{H}_3\right)}_3\left(H_{2}O\right)\right]}^{3+}$ have lesser $CFSE \left({∆}_O\right)$ value than ${\left[Co\left(en\right){\left(N{H}_3\right)}_4\right]}^{3+}$ therefore complex ${\left[Co\left(en\right){\left(N{H}_3\right)}_3\left(H_{2}O\right)\right]}^{+}$ absorbs longer wavelength for d-d transition :

Asked in: JEE Advanced 2018 (Paper 2)

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